Automatically generate texinfo.el internal autoloads

Automatically generate texinfo.el internal autoloads

* lisp/textmodes/texinfo.el: Replace manual autoloads.
* lisp/textmodes/makeinfo.el (makeinfo-region, makeinfo-buffer)
(makeinfo-recenter-compilation-buffer):
* lisp/textmodes/texnfo-upd.el (texinfo-make-menu)
(texinfo-all-menus-update, texinfo-start-menu-description)
(texinfo-indent-menu-description, texinfo-master-menu)
(texinfo-update-node, texinfo-every-node-update)
(texinfo-sequential-node-update, texinfo-insert-node-lines)
(texinfo-multiple-files-update):
Add autoload cookies, and set generated-autoload-file.